Khan Academy: Atomic Number, Mass Number, and Isotopes

A basic presentation to introduce some of the terminology regarding atomic weight, atomic structure, and atomic number awaits your students. An example of the calculations finding average atomic mass for carbon is given, and a way of...

Sal introduces chemistry students to the concept of "moles." He points out that a mole is number that helps a student to translate between grams and atomic mass units of any substance. Sal uses the element Aluminum to illustrate this...

Did you know that body armor actually contains uranium? Learn about how isotopes of the same element have different masses and unique physical properties.

Relative molecular masses sure have a lot of decimal places! Watch the video to learn how the number of particles in one mole of carbon-12 determines relative atomic and molecular masses. Viewers also learn how to calculate the...

Explaining group and period trends in atomic and ionic radii. [11:26]

An explanation of finding the probable location of an electron using quantum numbers to describe the orbitals. [12:00]

[Free Registration/Login may be required to access all resource tools.] In the following online tutorial students will be asked to define atomic number, mass number and understand how isotopes differ from one another. They will be able...

Video tutorial explains the difference between atomic weight and atomic mass in chemistry, and how it compares to the physics definitions of weight and mass. [8:53]

An explanation of the sizes of different atoms due to the number of electrons that are orbiting in energy shells. [11:25]

Video tutorial presents an introduction to the concept of a mole as a number. [9:43]